Audio system



FIG. 1 is a perspective view of an audio system as seen from the front, top and side;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is an opposite side view thereof; and,

FIG. 7 is a side view thereof.

The dotted line portions of the drawings represent environmental structure only and form no part of the claimed design. 

CLAIM The ornamental design for audio system, substantially as shown and described. 